I was for a long time seriously considering investing the time and dosh to 'go professional'. The final factor which convinced me not to do so was the neolithic labour relations enjoyed(?) by the airline industry world-wide.
On one side, protectionist unions seemingly stuck in the 60's, intent on protecting incompetents at all cost. On the other side, less than stellar management competency inflamed by unionist tactics considered obselete by coal miners.
I have been now a contractor for 10 years, paid to be competent and that alone. I can be sacked on 24 hours notice - anytime my current employer feels that they can do without me - and am happy this way. Anytime they annoy me I can leave in a minute and find another job tomorrow. My employer knows I am working for him because I want to and visa-versa.
Contrast this situation to the standard seniority driven situation within an airline. An unhappy pilot cannot pull up stakes and move to another airline because they would 'lose seniority'. Similarly, an airline cannot easily get rid of troublesome or unneccesary pilots without risking a ruckus. The pilot must live with the knowledge that perhaps the airline does not REALLY want him, and the airline must accept that some (or all) of their pilots would rather work somewhere else....